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BACKGROUND: At present, the research on the performance of Physiological Anchorage Spee's Wire System (PASS) appliance in China is still in its infancy. Quantitative analysis of the effect of vertical anchorage control using PASS appliance for teenagers is seldom reported. OBJECTIVE: To analyze the relationship between the vertical anchorage control and the changes of jaw plane angle and chin shape in patients with maxillary protrusion treated by PASS appliance. METHODS: 120 patients with maxillary protrusion were treated in the Second Affiliated Hospital of Xingtai Medical College from March 2016 to March 2019. The patients undergoing micro-implant anchorage treatment were randomly divided into observation group and control group, with 60 patients in each group. PASS appliance was used in the control group, and vertical support appliance between the first molars of both sides was used in the observation group. Oral X-ray lateral radiographs were used for imaging diagnosis to compare the effect and the difference of the chin shape between the two groups. RESULTS AND CONCLUSION: (1) At 4 weeks after treatment, the inner lower angle between the upper central incisor and the anterior skull base plane, the inner upper angle between the long axis of the lower central incisor and the mandibular plane, the angle of the mandibular plane, the distance between the two feet, and the distance from the lower lip bump to the aesthetic plane were significantly lower in the observation group than those of the control group (P < 0.05). The angle of the long axis of the upper and lower central incisors was significantly higher in the observation group than that of the control group (P < 0.05). (2) At 4 weeks after treatment, the apical point chin thickness, anterior chin thickness, chin depression, chin inclination, and chin soft tissue thickness of the observation group were significantly lower than those of the control group (P < 0.05), and the chin height, chin protrusion, and chin curvature and the depth of the soft tissue depression of the chin were significantly higher than those of the control group (P < 0.05). (3) It is concluded that in the treatment of patients with malocclusion, compared with PASS appliance, micro-implant anchorage combined with vertical control measures can effectively improve the shape of the chin, and the effect is significant. [ABSTRACT FROM AUTHOR]